In case if someone is still struggling with this, here's how you do Gradient Adaption in Fluent 2019:nnCreate 1 or more register(s) by following steps 2 & 3nGo to Domain -> Adapt -> Refine/CoarsennIn the 'Adaption Controls' dialog box, click on Cell Registers -> New -> Select the type of register you want to have and follow the required stepsnNow go back to Domain -> Adapt -> Refine/Coarsen -> Cell Registers -> New -> Field VariablenUnder the Derivative Option, Choose 'Gradient'nSelect the type of field variable you want. e.g.:Pressure, Static PressurenClick 'compute' to see the Max and Min values of the field variable you selectednChoose the type of refinement threshold in Type. e.g. Cells More ThannIf you chose say, 'Cells More Than', provide the threshold value in the 'Cells having value more than' boxnGive it a name and now click 'Save/Display' to see the cells that meet the criterion, and then hit 'Save' if you are satisfied. Then hit 'Close'nIn the 'Adaption Controls' dialog box, in the Refinement Criterion, from the drop down choose the gradient refinement criteria you just madenThen hit 'Ok' to mark or hit 'Adapt' to adapt the cellsnnYou can follow similar steps for coarsening the mesh as well.nnI hope this has helped someone.n